1. Technical Field
The invention relates to white iron, and more particularly to a composition and process for the manufacture of wear-resistant white iron.
2. Discussion of the Related Art
White iron alloyed with conventional carbide forming elements generally has high hardness and wear resistance. However, in its as-cast condition, absent subsequent thermal treatment, its ability to resist shock and its fatigue strength tend to be relatively low. Additionally, it tends to exhibit relatively low plastic deformability, which is believed to be a result of the presence of a brittle eutectic phase in its structure. Consequently, plastic working of such white iron tends to be commercially impractical because of such low deformability.
A process for the manufacture of alloyed white irons having high wear resistance and, specifically, high resistance to abrasive wear is discussed in G. J. Cox, "Progress in Abrasion-Resistance Alloy White Iron Development", Foundry Trade Journal, 1985, vol. 158, no. 3307, pp. 480, 483, 484, 486.
Another process for the manufacture of white iron is discussed in A. D. Sherman and A. A. Zhukov, "Cast Iron: A Handbook", Metallurgiya Publishing House, pp. 428-434 (Moscow, Russia, 1991). The process involves providing a cast iron structure including a eutectic that is based upon a stable vanadium carbide (VC). This is accomplished by adding a relatively large and costly amount, e.g., at least 6.28%, of vanadium. Other items which may be of interest are U.S. Pat. No. 4,030,944 (Sommer et al) dated Jun. 21, 1977; No. 0779428 (Soviet Union) dated Nov. 15, 1980; Patent No. 1,117,025 (Great Britain) dated Jun. 12, 1968; and "Deformable Moderately Alloyed White Irons," by Ju. N. Taran, et al, Metallovedenie i Termicheskaja Obrabotka Metallov, 1989, No. 5, pp. 35-43 (article with English Translation). See also, U.S. application Ser. No. 07/993,959, filed on Dec. 17, 1992, now U.S. Pat. No. 5,288,341 which is a continuation of Ser. No. 07/692,560, filed on Apr. 29, 1991 (abandoned), entitled "Process for Producing Deformable White Cast Iron", incorporated by reference.